Degradation Investigation of Catalyst Layer in PEM Fuel Cells Using Advanced Surface Analysis

The components within a polymer electrolyte membrane (PEM) fuel cell undergo degradation during use which lowers performance and efficiency.  In particular, the catalyst layer within the electrode is subjected to a variety of degradation mechanisms.  The significance of ionomer degradation has long been recognized and there is a growing body of literature to better understand the mechanism of ionomer degradation in the electrolyte membrane from academia, membrane manufacturers and the automotive industry. Ionomer degradation in the catalyst is far more complicated than in the membrane. The catalyst layer (CL) consists of ionomer, and carbon particles supporting highly dispersed Pt catalyst nanoparticles that form agglomerates with a random pore distribution and length scale on the order of 100 nm. In addition, it is the reaction site and the source of water production. But the ionomer degradation in the CL has not been adequately addressed or reported because the commonly used methods for degradation study of the CL and membrane, including electrochemical methods, have failed to identify ionomer degradation.